Acute decompensated heart failure (ADHF) is the leading cause of hospitalizations in older persons, which markedly worsen quality-of-life, increase mortality and health care costs, and have been declared a national priority by CMS. However, current management strategies have had only modest impact on rehospitalizations for ADHF, and recent trials have been negative, suggesting a need for a new approach. Multiple lines of evidence suggest that severe impairments in physical function strongly contribute to adverse outcomes in older ADHF patients. Even when stable and well-compensated, older patients with chronic HF have severe impairments in physical function, which markedly worsen as they transition to ADHF. These are further exacerbated by hospital-related factors, including forced bed rest. After discharge, patients continue to have marked impairments in strength, balance, mobility, and endurance. Most patients meet formal definitions of frailty, and some never recover baseline function. This occurs during the highest risk period for early rehospitalization and adverse outcomes. We hypothesize that this cascade of events resulting in persistent, severe physical dysfunction contributes to the high rates of rehospitalization in older HF patients. However, current HF management paradigms do not address the marked impairments in physical function, and neither chronic nor acute HF are approved indications for cardiac rehabilitation. Furthermore, exercise training trials have excluded ADHF, and have also not included the domains of balance, strength and mobility which are important for preventing injuries in frail, older patients. To address this critical evidence gap, we developed a novel, tailored, progressive, multidisciplinary 12-week rehabilitation intervention beginning during hospitalization and designed to address the specific deficits in physical function of older ADHF patients. In our pilot study, this intervention was safe and produced a 17.9% improvement in the Short Physical Performance Battery (SPPB) score and a 29.3% reduction in all-cause rehospitalizations. The change in the SPPB score explained 90% of the reduction in all-cause rehospitalizations. The primary aim of the proposed study (REHAB-HF) is to conduct a multi-center, randomized, controlled, single-blind trial in 360 older patients with ADHF to test the primary specific hypothesis that the REHAB-HF intervention will improve physical function, as measured by the SPPB. The secondary aim is to collect clinical outcomes data during 6-month follow-up to test the hypothesis that the REHAB-HF intervention group will have a reduced 6-month all-cause rehospitalization rate. The investigators are a cohesive, highly experienced multidisciplinary team from three well-established sites. By testing a novel intervention supported by multiple levels of evidence, the REHAB-HF trial will address a critical evidence gap in the care of older patients with ADHF, the most common Medicare discharge diagnosis. The REHAB-HF results could shift clinical management paradigms, improve function, reduce costs, and change health care policy for the 1 million older patients per year with hospitalized ADHF.